col=2

plot \
"qdc_1khz.hist"   u 0:2:(sqrt($2)) w ye t "1 kHz", \
"qdc_1khz.hist"   u 0:3:(sqrt($3)) w ye t "1 kHz"

#"qdc_10khz.hist"  u 0:2:(sqrt($2)) w ye t "10 kHz", \
#"qdc_100khz.hist" u 0:2:(sqrt($2)) w ye t "100 kHz"
